Improved rock-drill



UNITED STATES PATENT OFFICE.

JOHN M. LINSOOT'I, OF NEW YORK, N. Y.

IMPROVED ROCK-DRILL.

Specification forming part of Letters Patent No. 51,598, dated December19, 1865.

To all wh'om it may concern:

Be it known that I, JOHN M. LINscoTT, of the city and State of New York,have invented a new and useful Drill for Making Chambers in the Bottomof Holes in Rocks for Blasting Purposes, called LinscottsChamber-Drill;77 and I do hereby declare that the following specication,with the accompanying drawings, are snicient to enable any personskilled in the art or science to which it most nearly appertains to makeand use the same without further invention or experiment.

To enable others skilled in the art to make and use my drill, I willproceed to describe its construction and operation, and referring to thedrawings, in which the same letters indi.- cate like parts in eachof thefigures- Figure 1 represents an elevation. Fig. 2 is also an elevation.Fig. 3 represents the wedge and thimble. Fig.4 is a wedge. Figs. 5 and 6are the cutters in position. Figs. 7 and 8 are views of a single cutter.Fig. 9 is an end view of the wedge.

1The nature-of my invention consists in providing a drill so arrangedthat when forced down into the hole in the rock it strikes upon anannealed thimble or bolt, in which rests a wedge of hardened or temperedsteel, andforces out against the rock two steel cutters, thus forming achamber or recess near the bottom of the hole in which to place theexplosive material.

In the accompanying drawings, A is the shank or spindle ofthe drill, towhich is welded the lower part, ofiron, which is afterward casehardenedin such a manner as to let the wedgeshaped steel point G (shown at Fig.2) project into the cavity,in order to present a hard surface for thewedge Gr to butt against without breaking to pieces by reason of theconcussion or jar consequent upon the force of the blow given by thewedge O, which tits into the thimble or bolt D. Between these two piecesof steel, the C and D, are the sliders I I. These sliders I construct ofiron, (Swedish iron is the best,) to which are welded the steel cuttersH H', which are driven out against the sides ofthe hole into the rock bythe force of the blow upon the thimble-bolt D.

I make the thimble-bolt D of annealed steel. I anneal the steel for thepurpose of preventing the breaking or cleavage of it. The wedge G, Imake of hard or tempered steel.

In the chamber of the drill is a slot with crosssections or shouldersrunning across each side diagonally, in which the sliders I I', and towhich the cutters H H are welded, move. These sliders l make of Swedishiron, while the cutters are made of hardened steel highly tempered.

The lower portion of the drill I make of iron, casehardened, which iswelded to the wedge Gr and extends up the steel spindle A, in order toprevent the effects of the concussion which the blow ofthe drill wouldgive if made of steel.

The operation of my machine is as follows: When the drill is lifted upthe boltD falls till the shoulder of the wedge C rests on the lower partof the slot at L, Fig. l, thus allowing the sliders to move down thegroove or shoulders, (shown by the dotted lines E E F F, Fig. 2,) whichbrin gsA the cutters close to the drillshank. When the drill is droppedto the bottom of the hole the bolt D, with the wedge C,

is driven up forcibly and the sliders and attached cutters are moved outsuddenly against the sides of the hole as the wed ges are brought nearertogether, cutting right and left as the drill is operated and revolved.

When the cutters become dull they should be ground on a grindstone, soas to preserve the original temper, as they have the temper of cutlery.

The size of the hole or chamber made by my drill is about three inchesin diameter, with a working-model--say four and a half inches incircumferencenear the chamber. The explosive material is placed in thehole, completely filling up the chamber, when the fuse is introduced andthe hole leading to the chamber filled with earth firmly tamped.

By actual experiment made with my chamber-drill the explosive force ofthe material has been calculated to be atleast four times greater thanthat produced by blasting with the common drill alone, and the resultslargely preponderating in favor of my drill.

I believe I have described the construction of my drill for makingchambers in thel bottom and the Wedge C, constructed and operating ofholes for blasting rocks so as to enable any as and for the purposedescribed.

person skilled in the art to make and use it. 4C. The manner ofinelosiug or Surrounding I will now state what I desire to secure by thesteel spindle A, Wedge G, With iron, sub- Letters Paten t, to Wit:stautially in the manner set forth.

I claim- In Witness whereof l have hereunto set my 1. The cutters H Hand the sliders I I', conhand and aflXed my seal at the city of Newstruoted and operating substantially as and York this 5th day of May, A.D. 1865.

for the purpose specified. J. M. LINSCOT'I. [L S.]

2. The diagonal slots E E, in the manner and Witnesses: for the purposesubstantially as described. THos. HUNT,

3. The combination of the thimble-vbolt D FRANCIS J. MCTERNAU.

